Elevator control device



Oct. 8, 1957 e. R. CHADWICK ELEVATOR CONTROL DEVICE 2 Sheets-Sheet 1 Filed Sept. 9. 1954 INVENTOR. gaorjqa E, fhgdwi 0% Oct. 8, 1957 G. R. CHADWICK ELEVATOR CONTROL DEVICE 2 Sheets-Sheet 2 Filed Sept. 9. 1954 INVENTOR. gem 6 E, fizadw L'ck BY y ,fimn w United States Patent ELEVATOR CONTROL DEVICE George R. Chadwick, Chicago, Ill.

Application September 9, 1954, Serial No. 454,955

1 Claim. (Cl. 187-31) This invention relates to elevator control devices and more particularly to electro-mechanical safety devices applied to Meeker-type hatchway doors to prevent operation of an elevator when the doors are in open or partly open position. j

Freight elevator installations are usually provided with Meeker-type hatchway doors to close doorways leading from floor landings to elevator shafts, each door comprising upper and lower sections movable in a vertical plane toward each other into abutting engagement to close a doorway or movable away from each other to open the doorway. The doors are usually provided with electro-mechanical safety devices to prevent operation of the elevator when the door sections are in open position.

However, it is well known to those skilled in this art that some safety devices are not tamper-proof and could be rendered inoperative by an elevator operator to permit operation of an elevator when the doors are in open position. While an operator thus avoids the task of opening and closing the doors, it is obvious that such a practice can only result in injury to persons and damage to equipment.

It is, therefore, an object of the present invention to provide a safety device for conventional electro-mechanical interlocks for elevator doors to positively open an electrical circuit and thus prevent operation of the elevator when the doors are in open position.

Another object of the invention resides in the provision of a tamper-proof safety device for electro-mechanical interlocks in which the elevator cannot be operated when the doors are in open position except by removing the safety device or by shorting-out the electrical circuit.

A further object of the invention resides in the provision of a safety device which is relatively inexpensive to manufacture and install for use with electro-mechanical interlocks.

Another object of the invention resides in the provision of a safety device embodying means positively preventing closing of the elevator control circuit when the doors are in open position.

The invention embodies other novel features, details of construction and arrangement of parts which are hereinafter set forth in the specification and claim and illustrated in the accompanying drawings, wherein:

Fig. l is a front elevational view illustrating an elevator control device embodying features of-the invention, the device being shown as applied to a conventional electromechanical interlock for Meeker-type elevator doors, the doors being shown in their closed position.

Fig. 2 is an enlarged fragmentary front elevational view of same.

Fig. 3 is a side elevational view showing the parts of the control device in position to permit operation of an elevator.

Fig. 4 is a side elevational view, corresponding to Fig. 3, showing parts of the control device in position to preprovided to operate 88 to close or open a doorway 9 through a doorframe.

11 leading to an elevator shaft.

The door sections 6 and 7 are shown as supported in counterbalanced relationship by means of chains or cables 12-12 extending around pulleys 13-13, one end of each chain being secured to the upper door section 6 and the other end being secured to the lower door section 7. Each pulley 13 is journaled on a stud shaft' 14 mounted on the doorframe.

A metallic keeper blade 16 is shown as securedto the, upper end of the lower door section 7 for detachableinterlocking engagement with a latch 17 of a conventional electro-mechanical interlock 18. The safety device here:

in shown and hereinafter described is particularly suited for use with electro-mechanical interlocks now manufactured and sold by C. J. Anderson Company, type CV-l.

The electro-mechanical interlock 18 is shownas comprising a housing 19 secured in fixed position on the door frame 11 and formed with suitable bearings to receive a shaft 21 secured to the latch 17 intermediate the ends of the latter. A stud shaft 22 is secured to the upper end of the latch 17 to support a roller bracket 23 having a roller 24 journaled thereon for engagement by a conventional cam surface 25 provided on an elevator.

The lower end of the latch 17 is formed with an abutment shoulder 26 for engagement under the keeper blade 16 when the door sections 6 and 7 are in their closed position, with the elevator disposed out of registry with the doorway 9.

As the elevator moves into registry with the doorway, the cam surface 25 on the elevator acts through the roller 24 to move the latch shoulder 26 out of engagement with the keeper blade 16 to permit manual movement of the door sections 6 and 7 away from each other toward their respective open positions. A spring 27 is provided to yieldably resist pivotal movement of the latch 17 when the roller is engaged by the cam surface on the elevator, and to return the latch to its normal position for engagement of the shoulder 26 under the keeper blade 16 when the door sections are closed and the elevator has been moved to a position out of registry with the doorway 9.

A switch arm 28 formed of electrical insulating material is mounted for pivotal movement 'on a bearing element 29 secured on a shaft 31. The shaft- 31 is journaled in bearings formed in the housing 19 and has a switch actuating arm 32 keyed thereon for engagement by the keeper blade 16 to close an electrical elevator operating circuit by engaging a metallic bridge 33 on the arm 28 against the contacts 34 and 36.

As the door sections 6 and 7 approach their closed positions, the keeper blade 16 engages the upper end of the switch actuating arm 32, thus pivoting the switch arm 28 to a position in which the bridge 33 engages the contacts 34 and 36. As the door sections 6 and 7 are manually moved toward their open positions, the keeper blade 16 moves downwardly out of engagement with the switch actuating arm 28 which is then free to swing downwardly by gravity to pivot the switch arm 28 and its bridge 33 away from the contacts 34 and 36 to break the elevator control circuit.

The upper end of the switch arm 28 is normally enelement 29 by a spring 41 to permit relative movement between the switch arm and the bearing element after the bridge 33 engages the contacts '34 and 36.

""To'positively prevent rotational movement of the switch arm shaft 31 in a direction causing the bridge to engagethe contacts 34";11'121 when the door sections 6 and 7 are in their open positions, a lock out arm 42 is keyed on the shaft 31 with its free end disposed adjacent or against a cam'surface 43 'of a lock-out bar 44.

The lower end of the lock out bar 44 is shown as secured to a suitable bracket 45 mounted on the lower door section 7, the upper end of the bar being telescopically engaged within a tubular guide 46 mounted on the doortrame 11. The lower end of the bar 44 is ofiset at 47 toward the doorframe 11 and away from the lock out arm 42 to permit the lock out arm to pivot in a direction to close the elevator control circuit only when the door sections 6 and 7 are in their closed positions.

In the event an elevator operator should, when the door sections 6 and 7 are closed, tamper with the electro-mechanical interlock 18, as by inserting wedges of wood or paper bewteen the housing 19 and the switch actuating arm 32 to hold the latter in its raised position in which the'bridge 33 engages and closes the electrical control circuit between the contacts 34 and 36, manual movement of the door sections toward their open positions would cause the cam surface 43 to engage the lock out arm 42, thus either preventing opening of the door sections or causing the bridge 33 to move out of engagement with the contacts 34 and 36.

While this invention has been shown in but one form, it is obvious to those skilled in the art that it is not so limited, but is susceptible of various changes and modifications without departing from the spirit and scope of the claimed invention.

I claim:

In a safety device for elevator installations having upper and lower hatchway doors enacting to close a passage leading from a floor landing to an elevator shaft, a keeper blade secured to said lower door, an electro-mechanical interlock device mounted in fixed position adjacent said doors and having a switch actuating mechanism including a switch actuating arm engageable by said blade to alternately open and close an elevator control circuit responsive to alternate opening and closing movement of said doors, and mechanical lock-out means including a lock-out arm secured to said lower door to directly engage said switch actuating arm to prevent closing of said control circuit by said switch actuating mechanism when said doors are in open position, said lock-out arm having a cam surface for alternate movement into and out of operative engagement with said switch actuating arm, the free end of said lock-out arm being telescopically guided within a fixed tubular guide member.

References Cited in the file of this patent UNITED STATES PATENTS Boyce Feb, 1, 1916 Schweig Mar. 4, 1941 Wilmot May 6, 1941 

